Apparatus for controlling engine idling speed



Sept. 11, 1956 OLSON ETAL APPARATUS FOR CONTROLLING ENGINE IDLING SPEED Filed Sept. 10, 1953 INVENTORS GALE FBselw/vcaez BY ELMEE OLSON 0 JOHN VAHOE 7 AQOENEY United States Patent Ofice 2,762,235 Patented Sept. 11, 1956 APPARATUS F GE CUNTROLLDN'G ENGINE IDLING SPEED Elmer Olson and Gale F. Berninger, Rochester, N. Y., and John V. Ahoe, Detroit, IVIich., assignors to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application September 10, 1953, Serial No. 379,401

16 Claims. (Cl. 74472) This invention relates to mechanism for controlling the idling speed of an internal combustion engine and, more particularly, to a means for controlling the speed of the engine of an automotive vehicle when the underhood temperature adjacent the engine is higher than the under-hood temperature normally maintained when the engine is idling.

It has been found that with automotive vehicles which are provided with air conditioning equipment to cool the interior space within the body of the vehicle, the temperature under the hood in the space surrounding the engine becomes very high when the engine idles for any appreciable period, but when the engine is operating under load and the vehicle is in motion, such excessive temperature conditions do not exist. It has also been determined that with the excessive temperatures that are encountered, good carburetion, when idling at normal speed, is impossible and the engine will run irregularly with a tendency to stall, but that if the idling speed is sufliciently increased, satisfactory idling operation can be obtained.

It is not desired to increase the idling speed when the vehicle is stopped for a brief period as when waiting for a change of traffic lights, for example, because in the first place, the temperature under-hood is not high enough under such circumstances to make the increase in idling speed necessary. Also, under such circumstances, in a vehicle equipped with an automatic transmission, the transmission control lever is not generally set in neutral position and if the idling speed was increased to any considerable extent, it would bring about movement of the vehicle.

It is, therefore, the principal purpose of the present invention to provide a means for automatically increasing the idling speed of the engine of an automotive vehicle, particularly one equipped with air conditioning apparatus, which will be effective when the engine idles for any considerable length of time.

When there is prolonged idling, it is customary to move the transmission control lever to its neutral position so that in a vehicle equipped with a standard transmission it will'not be necessary to hold the clutch in disengaged position, and with an automatic transmission the latter will not-be in a drive position. to the present invention, the above object is achieved by the" provision of means, operable when the transmission Accordingly, according control lever is moved to its neutral position, which will eifect 'an "increase in idling speed to approximately 700 M-Llbut which in all other positions of the transmission control lever is ineffective so that hot idle speed of the engine will be normal, for example, 350 to 400 R. P. Another purpose of the invention is to provide mechanism for accomplishing the functions referred to entirely independently of the conventional fast idle mechanism, ..which is provided in most carburetors in use at the present day, to automatically increase the idling speed of the engine as the temperature decreases and without in any way interfering with the mechanism.

According to the present invention, these objects are accomplished by means of a spring-pressed plunger which moves the throttle partly toward open position, whenever the engine is inoperative or when the transmission con trol lever is in neutral position, sufficiently to obtain an engine speed of approximately 700 R. P. M. Under all engine operating conditions, when the transmission control lever is not set in neutral position, a diaphragm operated by engine suction is efiective to move the plunger to inoperative position, against the force of the spring, but when the transmission control lever is moved to neutral position, a switch operable thereby is closed and a solenoid is energized to move a control valve to a position Where it admits air to eliminate the effect of suction on the diaphragm, and permits the spring to become effective to move the plunger to throttle opening position.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred embodiment of the present invention is clearly shown.

In the drawings:

Figure 1 is a side elevation of a conventional carburetor equipped with the device which is the subject of this invention and a diagram of the control circuit therefor;

Figure 2 is a detail section of the throttle operating mechanism and control valve.

The device which constitutes the present invention is illustrated in the drawings as associated with acarburetor of conventional down-draft type. As illustrated, the carburetor is of substantially the same construction as shown in the pending application of Olson and Dermond, S. N. 264,136, filed December 29, 1951, and has plural outlets which communicate with corresponding outlets in the manifold, but so far as the present invention is concerned, it is entirely immaterial Whether the carburetor is of the single or plural outlet type. Also, the specific construction of the carburetor is of no importance so far as the present invention is concerned. Therefore, the drawing discloses only an elevation of the outside of the carburetor, and the interior construction is not shown.

The carburetor illustrated is formed of three separate castings, the air inlet casting" 2, the casting 4 in which the constant level float chamber is positioned and an outlet casting 6 in which are formed the plural outlets and which has an attaching flange 8 adapted to be secured to the intake manifiold in the conventional manner. The several outlets are controlled by manually operated throttle valves which are secured to shafts 10 and 12. The shaft 10 is a primary throttle shaft and the throttle 14 secured thereto and indicated in dotted lines is the primary throttle. This throttle is open at all operating speeds and after it is opened to a predetermined extent, the operation of shaft 10 efliects movement of shaft 12 to open the secondary throttle mounted on it. To eifect this operation, the shaft 10' carries an operating arm 16 having a slot 18, the end of which engages the bent-over end of an operating link 20 which extends into slot 18, after the throttle 14 has reached a partly open position, and through the medium of this link moves an arm 22 secured to the secondary throttle shaft to open the secondary throttle. The primary throttle shaft 10 is operated from the conventional accelerator pedal through the usual form of operating connections and the shaft 10 moves in a counterclockwise direction to open throttle 14.

The primary throttle occupies a nearly closed position for normal hot idling which is determined by an adjustable stop screw, which is on the opposite" side of the operation of such fast idle carburetor from that shown, and is of standard construction. This stop is adjusted to set the throttle in proper position for satisfactory idling under normal conditions.

According to the present invention, means are provided for moving the throttle 14 partly toward open position under certain circumstances so that the engine will idle faster than the normal idling speed. The mechanism for moving the throttle toward open position to increase the idling speed comprises an actuating member 24 which is threaded in a stud 26, slidable in a bushing 28 suitably secured in the lower end of a bracket 30 which, at its upper end, is bent overto form a flat plate 32 which is secured by screws 34 or in any other suitable way, to the top of the float chamber which is a part of casting 2.

The bushing 28 has flanges 29a engaging the supporting bracket 30 and 29b engaging the inside of shell 36, which forms half of a diaphragm chamber. The shell is clamped between flange'29b of the bushing and the supporting bracket 30, to hold the diaphragm chamber in position. Clamped betweenthe peripheral edges of shell 36 and a cooperating shell 38 is a flexible diaphragm 40. The shell 36 is crimped over the edge of the shell 38 so that the diaphragm is clamped between the shells tightly enough to form an air-tight joint. The diaphragm has a central opening through which the stud 26 extends and on opposite sides of the diaphragm are metal plates 42 and 44, which are clamped between a flange 46 adjacent the end of the stud 26 and a'flange 48 formed by a shearing tool, or otherwise, which extends from the stud 'on the opposite side of the diaphragm assembly. It will be understood, however, that any suitable means can be employed to secure the diaphragm and the plates 42 and 44 in fixed position on the stud 26. Between the plate 44 and the shell 38 there is a compression spring 50 which normally holds the diaphragm in the position shown in the drawings. This spring surrounds the end of the stud 26 and is held in position against lateral movement by a finger 52 which is cut out of the plate 44 and bent so that it extends in a direction normal to the surface of the plate.

Extending into a central opening in shell 38 is the reduced end of a member 53 which is riveted over the shell 38 to clamp such shell against shoulder 54 to form an air-tight joint therewith. The member 53 has an opening into which projects a suction conduit 56, the other end of which is connected to the intake manifold in any suitable way. This conduit 56 may be press-fitted in the member 53 as shown, or connected theretoby a suitable nipple, or otherwise, and communicates the suction of the intake manifold to a bore 58, extending axially of the member 53 and connecting with the interior of the shell 38 so as to communicate the manifold suction to the diaphragm. When the suction is sufliciently high, great enough to overcome spring 50, it will move the diaphragm assembly toward the right against the force of the spring, for a purpose to be more fully described later. The right end of the bore 58 constitutes a valve seat for the valve 60 and connecting with the bore 58 adjacent such valve seat is an opening 62, which will admit atmosphere to the bore 58 when the valve 60 is opened by movement thereof to the right.

The member 53 at the right end thereof is enlarged to form .a mounting plate 64. Positioned adjacent the right face of this mounting plate is a gasket 66 which is positioned between the plate and a housing 70 which 'may be secured to. theplate'by any desirable form of securing means, and positioned inside the housing is a solenoid having a winding 72 while the valve 60 is formed integral with an' enlarged head 73 which is the armature of the solenoid. v a a A stud 74 has a reduced end which extends through the housing 70 and at 76 is riveted over the outer surfaceof the housing so as to hold the stud in fixed position, the housing and an insulating washer 78 being clamped between the riveted end of the stud and a flange 79 integral with the stud, as illustrated. This stud has an axial recess 80 in which is received a compression spring 82 which normally moves the valve 60 to the left to its closed position, as shown in Fig. 2 so that normally, unless the solenoid is energized, the valve 60 is in its closed position and the passage 62 is cut oif and atmosphere is not admitted to the bore 58.

The winding 72 of the solenoid is positioned between flange 79 and a flange 83 at the end ofthe stud 74 and is connected by leads 84 and 86 to terminals 88v and 90, respectively, the terminal 88 being grounded at 92 and the terminal being connected by a wire 94 to a fixed contact 96 of a switch, which is shown diagrammatically in Fig. 1. Cooperating with the contact 96 is a spring contact 98, which is also shown diagrammatically in Fig. l and is manually operated by means later described so that when closed, the solenoid will be energized to open the valve 60.

The contact 98 is connected by a wire 100 to the ignitic-n switch 102 and when the latter is closed, such contact is connected with the battery 104 so that the switch comprising the contacts 96 and 98 is in series with the ignition switch and will not efiect energization of the solenoid when it is closed unless the ignition switch is also closed. 7

A wire 06, which is connected with the wire 100, leads to the engine ignition apparatus, which'is of conventional form and need not be described. a

The operation of the switch comprising contacts 96 and 98 is controlled by the mechanism which controls the setting of the vehicle transmission and which is illustrated diagrammatically in Fig. 1. Such mechanism includes a shaft which is positioned adjacent the steering wheel of the vehicle and is operated by a lever 112 to change the setting of the transmission from neutral, which is indicated by'the letter N on the indicating means 114, to the various driving positions in which the lever 112 is adapted to be set during operation of the vehicle;

Whenever the lever 112 is moved to the neutral position as illustrated, a cam 113 will move the contact 98 into engagement with the contact 96 and if the ignition switch is closed at the time this movement takes place, the solenoid previously described will be energized to move valve 69 to the right.

This movement of the valve will place the passage 6 in communication with the bore 58 so that atmospheric pressure will be communicated through such bore to the diaphragm chamber in the space at the right of the'diaphragm assembly and will reduce the degree of suction communicated thereto by the manifold so that the spring 55 may move the diaphragm to the left. This will move the stud 26 and the operating member 24 to the left so that, through the medium of engagement of the member 24 with the arm 16 which is secured to the end of the primary throttle shaft, such arm will be moved to the left, or counter-clockwise, and the throttle will be opened to an extent determined by the adjustment of the oper ating member 24in the stud 26.

As pointed out previously, under certain circumstances,

when the engine is idling for a considerable length ot time, the heat adjacent the engine in a vehicle equipped with air conditioning apparatus becomes so great :that V the engine will not operate satisfactorily when -idiing at the normal idling speed and the mechanism above described is provided for the purpose of'automaticallyf opening the throttle further under the conditions specified so as to increase the idling speed toapproximatel y 700' R. P. M. 'It is desirable to do this only when the ltransmission control is set in its neutral position for, as previously set forth, when the vehicle is stopped forgonly duration has to be made and it is desired to keep the engine running, the transmission control lever may be moved to its neutral position and when so moved, the contact 98 is moved into engagement with the contact 96 to energize the solenoid and move the valve 60 to the right, as described.

When the engine is idling, with the valve 60 closed, the manifold vacuum or suction is sufficient to move the diaphragm assembly to the right against the force of the spring 50 so that the arm 16 on the end of the throttle shaft 19 can move in a clockwise direction far enough to permit a normal idling stop secured to the opposite end of the shaft to engage a fixed stop on the carburetor housing, in which position the throttle 14 will be more nearly closed than as shown in the drawings and the idling speed will be approximately 350 to 400 R. P. M. However, as soon as valve 68 is opened as described, the admission of atmosphere to the bore 58 will so reduce the manifold vacuum which is effective upon the diaphragm that the spring 50 will move the stud 26 and the operating member 24 to the left far enough to move the arm 16 and the throttle shaft 10 to a slightly more open position so as to increase the idling speed to approximately 760 R. P. M., as previously set forth.

The idle stop mechanism which controls the idling speed whenever the transmission control lever is not in neutral position, is not shown as its specific construction is not material with respect to the present invention but may be of exactly the same construction as shown in copending application previously referred to. It will also be understood that when the temperature is low and the engine idling with the transmission control lever in one of its drive positions, the idling will be maintained at a speed considerably greater than the normal hot idling speed by means of the conventional fast idling mechanism which is not shown but may be of the same construction as that disclosed in the copending application above referred to. The mechanism disclosed herein for increasing the idling speed when the transmission control lever is moved to neutral position is entirely independent of the conventional fast idle mechanism which is effective only at relatively low temperatures and becomes wholly ineffective as soon as the engine reaches normal operating temperature.

While the embodiment of the present invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted.

What is claimed is as follows:

1. Apparatus for controlling the idling speed of the engine of an automotive vehicle comprising in combination, a carburetor for supplying a combustible mixture of fuel and air to said engine having a throttle valve for controlling the quantity of mixture supplied to the engine, means for moving the throttle toward open position for increasing the idling speed of the engine, a transmission control' lever adjustable to neutral and to a plurality of driving positions and means operable by said lever when moved to its neutral position only to cause operation of said means to move the throttle toward open position.

2. Apparatus for controlling the idling speed of the ngine of'an automotive vehicle comprising in combination, a carburetor for supplying a combustible mixture of fu l and air to said engine having a throttle valve for controlling the quantity of mixture supplied to the engine, for moving the throttle toward open position for increasing the idling speed of the engine, a transmission ontr l lever adjustable to neutral and to a plurality of r i g positions and operable to bring about operation f aid last-named means when the transmission control lever is moved to its neutral position, and means operable to turn the throttle to its normal idling position when i love? is moved to any of its driving positions.

3- Apparatus for controlling the idling speed of the E gine of an automotive vehicle comprising in combinait, a carburetor for supplying a combustible mixture of fuel and air to said engine having a throttle valve for controlling the quantity of mixture supplied to the engine, means for moving the throttle toward open position for increasing the idling speed of the engine, a transmission control lever adjustable to neutral and to a plurality of driving positions and operable to bring about operation of said last-named means when the transmission control lever is moved to its neutral position, and means operable by engine suction to return the throttle to its normal idling position when said lever is moved to any of its driving positions.

4. Apparatus for controlling the idling speed of the engine of an automotive vehicle comprising in combination, a carburetor for supplying a combustile mixture of fuel and air to said engine and having a throttle valve for controlling the quantity of mixture supplied to the engine, throttle operating means for moving the throttle toward open position for increasing the idling speed of the engine, a transmission control lever adjustable to neutral and driving positions, and means controlled jointly by said lever when in neutral position and by engine suction for controlling the operation of said throttle operating means.

5. Apparatus for controlling the idling speed of the engine of an automotive vehicle comprising in combination, a carburetor for supplying a combustible mixture of fuel and air to said engine having a throttle valve for controlling the quantity of mixture supplied to the engine, throttle operating means for moving the throttle toward open position for increasing the idling speed of the engine, means operable by engine suction to prevent operation of said last-named means, a vehicle control member and means operated by said vehicle control member when moved to one of its controlling positions to render the suction operated means inoperative so that whenever the vehicle control member is so moved, the throttle operating means becomes effective to partly open the throttle.

6. Apparatus for controlling the idling speed of the engine of an automotive vehicle comprising in combination, a carburetor for supplying a combustible mixture of fuel and air to said engine having a throttle valve for controlling the quantity of mixture supplied to the engine,

- throttle operating means for moving the throttle toward open position for increasing the idling speed of the engine, means operable by engine suction to prevent opera tion of said last-named means, a transmission control lever movable to neutral and drive positions, and means operated by said control member when moved to its neutral position to render said suction operated means inoperative, whereby the throttle operating means is rendered effective to partly open the throttle.

7. Apparatus for controlling the idling speed of the engine of an automotive vehcicle comprising in combination, a carburetor for supplying a combustible mixture of fuel and air to said engine having a throttle valve for controlling the quantity of mixture supplied to the engine, throttle operating means for moving the throttle toward open position for increasing the idling speed of the engine, means operable by engine suction to prevent operation of said last-named means, a transmission control lever movable to neutral and drive positions, means operated by said lever when moved to its neutral position to render the suction operated means ineffective and means operable by said control lever when moved to drive position to render the last-named means inoperative, whereby the suction operated means becomes operative whenever said lever is in drive position.

8. Apparatus for controlling the idling speed of the engine of an automotive vehicle comprising in combination, a carburetor for supplying a combustible mixture of fuel and air to said engine having a throttle valve for controlling the quantity of mixture supplied to the engine, throttle operating means for moving the throttle toward open position for increasing the idling speed of the engine, means operable by engine suction to prevent operation of said lastmamed means, a transmission control lever movable to a neutral and to aplurality of drive positions, means operated by said lever when moved to its neutral position to render the suction operated means ineffective, and means operable by said control lever when moved to any of its drive positions to render the last-named means inoperative, so that the suction operated means becomes efl ective to prevent operation of the throttle operating means. 7

9. Apparatus for controlling the idling speed of the engine of an automotive vehicle comprising in combination, a carburetor for supplying a combustible mixture of fuel and air to said engine having a throttle valve for controlling the quantity of mixture supplied to the engine, throttle operating means for moving the throttle toward open position for increasing the idling speed of the engine, means operable by engine suction to prevent operation of said last-named means, a transmission control lever movable to neutral and drive positions, a valve operable when open to admit air to the suction operated means so as to nullify the elfect of suction and render said suction operated means ineifective, means for moving the valve to open'position, and mean operated by the transmission control lever when moved to its neutral position to cause said valve opening means to become operative.

10. Apparatus for controlling the idling speed of the engine of an automotive vehicle comprising in combination, a carburetor for supplying a combustible mixture of fuel and air to said engine having a throttle valve for controlling the quantity of mixture supplied to the engine,

throttle operating means for moving the throttle toward open position for increasing the idling speed of the engine, means operable by engine suctionto prevent operation of said last-named means, a transmission control lever movable to neutral and drive positions, a valve operable when open to admit air to they suction operated means so as to nullifythe effect of suction and render said suction operated means ineffective, means for moving the valve to. open position, means operated by the transmission control lever when moved to its neutral position to cause said valve opening means to become operative, means for closing said valve, said last-named means being rendered effective by movement of the transmission control lever to drive position.

11. Apparatus for controlling the idling speed of the engine of an automotive vehicle comprising in combination, a carburetor for supplying a combustible mixture of fuel and air to said engine having a throttle valve for controlling the quantity of mixture supplied to the engine, throttle operating means for moving the throttle toward open position for increasing the idling speed of the engine, mean'soperable by engine suction to prevent operation of said last-named'means, a solenoid operable when energized to render the suction operated means inoperative so as to permit operation of the throttle operating means, a vehicle control member and means operated thereby when moved to one of its positions to eflect energization of the solenoid.

12..Apparatus for controlling the idling speed of the engine of an automotive vehicle comprising in .combination, a carburetor for supplying a combustible mixture of fuel and air to said engine having a throttle valve' for controlling the quantity of mixture supplied to the engine, throttle operating means for moving the throttle toward open position for increasing the idling speed of the engine, means operable by engine suction to prevent operation of said. last-named .means, a. vehicle control member, a solenoid, a valve movable bysaid solenoid when energized to a position to admit air to said suction operated means so as to render said last-named means inoperative and permit operation of the throttle operating means, and means operated by the vehicle control member when moved to one of its positions for effecting energization of said solenoid.

13. Apparatus for controlling the idling speed of the engine of an automotive vehicle comprising in combination, a carburetor for supplying a combustible mixture of fuel and air to said engine having a throttle valve for controlling the quantity of mixture supplied to the engine, throttle operating means for moving the throttle toward open position for increasing the idling speed of the engine, means operable by engine suction to prevent operation of said last-named means, a transmission control lever movable to neutral and drive positions, a solenoid, a valve movable by said solenoid when energized to a position to admit air to said suction operated means so as to render said last-named means inoperative and permit operation of the throttle operating means, and means operated by the transmission control lever when moved to neutral position for effecting energization of the solenoid.

14. Apparatus for controlling the idling speed of the engine ofan automotive vehicle comprising in combination, a carburetor for supplying a combustible mixture of fuel and air to said engine having a throttle valve for controlling the quantity of mixture supplied to the engine, throttle operating means for moving the throttle toward open position for increasing the idling speed of the engine, means operable by engine suction toprevent operation of said last-named means, a solenoid-operable when energized to render the suction operated means inoperative so as to permit operation of the throttle operating means, a vehicle control member and a switch, adapted to be closed by the vehicle control member when moved to one of its positions for efiecting energization of the solenoid.

15. Apparatus for controlling the idling speed of the engine of an automotive vehicle comprising in combination, a carburetor for supplying a combustible mixture of fuel and air to said engine having a throttle valve for controlling the quantity of mixture supplied to the engine, throttle operating means for moving the throttle toward open position for increasing the idling speed of the engine, means operable by engine suction to prevent operation of said last-named means, a transmission control lever movable to neutral and drive positions, a solenoid, a valve movable by said solenoid when energized to a position to admit air to said suction operated means so as to render said last-named means inoperative and permit operation of the throttle moving means, and a switch adapted to be closed by the vehicle control member when moved to one of its positions for efiecting energization of the solenoid.

16. Apparatus for controlling the idling speed of the engine of an automotive vehicle comprising in combination, a carburetor for supplying a combustible mixture of fuel and air to said engine having a throttle valve for controlling the quantity of mixture supplied to the engine, means for moving the throttle toward open position for increasing the idling speed of the engine, a transmission control lever adjustable to neutral and driving positions,

and means operable by said lever when moved to neu position to cause operation of said means to mov t throttle toward open position.

Neracher et a1. Feb. 29, 

